Control apparatus for heaters



July 12, 1966 R. c. SPOONER CONTROL APPARATUS FOR HEATERS 2 Sheets-Sheet 1 Filed Sept. 28, 1964 INVENTOR RICHARD QSPOOIVEH QOOO ATTORNEY July 12, 1966 R. C. SPOONER Filed Sept. 28, 1964 2 Sheets-Sheet 2 (80 PREHEA'IER 46 5 L FuELvAu/E f1 -5 f 38 W GOLD HOT 78 d. L BURNER i? THERMOSTAT 68 8 HEATER THERMOSTAT 80 46 PREHEATER 82 FUEL VALVE ea 14 38 76 l2 \COLD HOT M 150 l BURNER INVENTOR THERMOSTAT T RICHARD asPoo/wsn r BY A'ITORNEY5 United States Patent 3,260,298 CONTROL APPARATUS FOR HEATERS Richard C. Spooner, Fairview Park, Ohio, assignor to Hupp Corporation, Cleveland, Ohio, a corporation of Virginia Filed Sept. 28, 1964, Ser. No. 399,703 3 Claims. (Cl. 158-28) This invention relates to liquid fuel fired heaters which deliver a continuous stream of heated air or liquid and more particularly to improved control circuits for such heaters.

In their preferred form the heaters are particularly useful in heating vehicles. These heaters, apart from their associated control systems, are generally the same as the heaters disclosed and claimed in Patent No. 3,144,- 862. Because of their superior combustion characteristics these heaters are adapted to operate efiiciently with a wide variety of fuels. For this reason, the control circuits for such heaters must be able to initiate combustion under a wide variety of conditions and with highly volatile fuels such as gasoline or with fuel of volatility such as diesel oil.

It is the principal object of the present invention to provide improved control circuits for such heaters which assure the initiation of combustion under adverse conditions and despite the use of fuels of low volatility such as diesel oil.

It is a further object of the present invention to provide improved and simplified control circuits for such heaters particularly for heaters used in vehicles which are operated only when the vehicle engine is running and an operator is present.

It is also an object of the present invention to provide control circuits for such heaters which eliminate expensive components thus reducing the cost and bulk of the circuits while increasing their reliability.

Additional objects and advantages of the present invention will become apparent as the description proceeds in connection with the accompanying drawings in which:

FIGURE 1 is a central vertical section of a typical heater to which the control circuits of the present invention may be applied;

FIGURE 2 illustrates diagrammatically one form of the control circuit for the heater of FIGURE 1; and

FIGURE 3 illustrates a second form of control circuit for the heater of FIGURE 1.

Referring now more particularly to the drawings, the principal components of the heater of FIGURE 1 are the fresh air blower 10, the blower motor 12, the combustion air inlet duct assembly 14, the combustion air blower 16, the combined combustion chamber-burner assembly 18, and the heat exchanger assembly 20. These components are suitably mounted in generally co-axial alignment within a tubular casing member 22 having at one end a cover member 24 providing a fresh air inlet opening and having at its opposite end a second cover member 26 providing a heated fresh air outlet opening.

Additional components of the heater include a commutator assembly 28 connected to an externally mounted coil 30 which in turn is connected to a spark electrode 32 projecting inwardly into close proximity with a fuel distributer assembly 34 to which fuel is supplied through a conduit 36 leading from the downstream side of a solenoid operated fuel valve 38.

The fuel distributer assembly 34 preferably comprises a mat of ceramic fibers 40 held against a backing plate 42 by a metal screen retainer 44 which also provides a ground for the spark electrode 32. A pre-heater assembly 46, preferably comprising a coil of sheathed resistance wire suitably secured to a mounting plate 48, is provided to facilitate initiation of combustion during cold weather Ice particularly where fuels of low volatility are used. Also, secured to the mounting plate 48 is a burner thermostat 50.

In operation, after combustion is initiated and the blower motor 12 is placed in operation, air is drawn in through the duct assembly 14 by the combustion air blower 16 and delivered to the combustion chamber assembly through a plurality of small openings 52, the resulting combustion products then flowing through one or more passages 54 leading to the interior of the heat exchanger assembly 20 from which the combustion products pass to the exterior of the device through one or more outlets 56. At the same time fresh air is moved through the apparatus by the fresh air blower 10 passing over and around the combustion chamber assembly 18 and the heat exchanger for delivery as desired through the opening formed in the cover 26. For additional details of the construction of this heater and its operation reference may be had to the aforesaid Patent No. 3,144,862.

Referring now to the control circuit of FIGURE 2, this circuit includes main power lines 60 and 62, the former being connected to a source of power such as the vehicle battery, the latter being grounded. Power line 60 is connected through the ignition switch 64 to the engine ignition circuit indicated generally at 66. The control circuit includes two main parallel circuits connecting power lines 60 and 62. The first circuit includes a manually operated heater control swtch 68 and parallel branch circuits, one including pre-heater 46 and the other including fuel valve solenoid 38, the blower motor 12, and the ignition circuit comprising the coil 30, electrode 32, screen 44, commutator 28 and the condenser 70. The other circuit leads directly from the power line 60 through a relay coil 72 and the burner thermostat 50. Relay coil 72, when energized, opens a normally closed contact and closes a normally open contact 82. The two main parallel circuits may be interconnected by :a flame switch assembly 74, which includes contact 76 closed when the burner is out of operaton and the contact 78, closed when the burner is in operation.

When the system is at rest with switch 68 open, the pre-heater will be de-energized, the fuel valve will be closed, the flame switch contact 76 will be closed, the motor 12 will be de-energized and the burner thermostat 50 will be open. Assuming both the ignition switch 64 and the heater switch 68 are closed, a circuit will be completed through the pre-heater 46, warming the burner and particularly the fuel distributer. When this region of the burner reaches a pre-determined temperature sufficient to provide vaporization of the fuel, the contacts of burner thermostat 50 will close to complete a circuit through relay coil 72 to thereby open contact 80 and close contact 82. The opening of contact 80 de-energizes the pro-heater 46. Closing of contact 82 energizes the fuel valve, blower motor 12 and the ignition system. Assuming normal operation, combustion will be initiated imme diately. When the burner has reached operating temperature the flame switch 74 will open contact 76 and close contact 78 thus providing a direct circuit from the battery to the blower motor 12 and the ignition system. Accordingly, if the heater operation is stopped by opening either the ignition switch '64 or the heater switch 68, the fuel valve will close but the ignition, spark and combustion air blower will continue to operate to complete the combustion of residual fuel to eliminate smoke and to cool the burner until the lower temperature causes the flame switch to re-open contact 78 and close contact 76.

If combustion should cease, for example, because the burner runs out of fuel or if the burner fails to ignite initially the burner thermostat will open or remain open de-energizing relay coil 72 thus permitting contact 80 to reclose to re-energize t-he pre-heater and permitting contact 82 to open to permit the fuel valve to close. The flame switch '74 closes contact 76 and opens contact 78 thus shutting off the blower motor 12 and the ignition system. Energization of the pre-heater then causes the starting cycle to be repeated until the burner is again burning or the operator opens either the ignition switch or the heater switch.

The circuit of FIGURE 3 is the same as the circuit of FIGURE 2 except for the addition of a heater thermostat 84 subject to the temperature of the space to be heated, and a relay having a coil 86 and a normally open contact 88 in series with pre-heater, fuel valve, motor and the ignition circuits. In operation assuming that the ignition switch 64 and the heater switch 68 are closed and that the temperature of the space falls below the level at which contacts of thermostat 84 are closed, relay coil 86 will be energized closing contact 88. Thereafter the operation of the control circuit of FIGURE 3 will be the same a s that of FIGURE 2.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. Control apparatus for a fuel burning heater having a motor driven blower for supplying combustion air, a normally closed solenoid operated fuel valve, an electric igniter, a combustion chamber having a fuel distributer and a pre-heater for said fuel distributer, said control apparatus comprising a main switch connected in series with a power source said pre-heater, said valve, said motor and said igniter, a normally closed contact in series with said pro-heater, a normally open contact in series with said valve, said motor and said igniter, a relay coil [for closing said normally open contact and opening said normally closed contact, a normally open thermostat in series with said relay coil, said thermostat being subject to the temperatureof said combustion chamber in the region of said pre-heater whereby when said main switch is closed, said pre-heater will be energized and thereafter said preheater will close said thermostat to energize said relay to de-energ-ize said pre-heater and simultaneously energize said fuel valve, motor, and igniter to establish combustion in said heater.

2. Control apparatus according to claim 1 together with means responsive to the temperature of said combustion chamber for by-passing said main switch and said normally open contact, to connect said motor and said igniter directly to said power source when said burner is in operation.

3. Control apparatus for a fuel burning heater having a motor driven blower for supplying combustion air, a normally closed solenoid operated f-uel valve, an electric ignitor and a combustion chamber having -a fuel distributer and a pre-heater for the said fuel distributer, said control apparatus comprising a main switch connected in series with a power source and operable when closed to energize said pre-heater, said valve, said motor and said ignitor, a first thermostat in series with said main switch, said first thermostat being subject to the temperature of the air in the space served by said heater, a normally closed contact in series with said pre-heater, a normally open contact in series with said valve, said motor and said ignitor, a relay coil for closing said normally open contact and opening said normally closed contact, second thermostat in series with said relay coil, said second thermostat being subject to the temperature of said combustion chamber in the region of said .pre-heater whereby when said main switch is closed and said first thermostat is closed said preaheater will be energized and thereafter said pre-heater will close said second thermostat to energize said relay to de-energize said pre-heater and simultaneously energize said fuel valve, said motor and said ignitor to establish combustion in said heater.

References Cited by the Examiner UNITED STATES PATENTS 2,168,859 8/1939 Bergey 15828 2,458,630 1/1949 Palko 158-280 X 2,662,589 1 2/1953 Aubert l5828 3,078,838 2/1963 Broecker 158-28 JAMES W. WESTHAVER, Primary Examiner. 

1. CONTROL APPARATUS FOR A FUEL BURING HEATER HAVING A MOTOR DRIVEN BLOWER FOR SUPPLYING COMBUSTION AIR, A NORMALLY CLOSED SOLENOIDE OPERATED FUEL VALVE, AN ELECTRIC IGNITER, A COMBUSTION CHAMBER HAVING A FUEL DISTRIBUTER AND A PRE-HEATE FRO SAID FUEL DISTRIBUTER, SAID CONTROL APPARATUS COMPRISING A MAIN SWITCH CONNECTED IN SERIES WITH A POWER SOURCE SAID PRE-EHEATER, SAID VALVE, SAID MOTOR AND SAID IGNITER, A NORMALLY CLOSED CONTACT IN SERIES WITH SAID PRE-HATER, A NORMALLY OPEN CONTACT IN SERIES WITH SAID VALVE, SAID MOTOR AND SIAD IGNITER, A RELAY COIL FOR CLOSING SAID NORMALLY OPEN CONTACT AND OPEN SAID NORMALLY CLOSED CONTACT, A NORMALLY OPEN THERMOSTAT IN SERIES WITH SAID RELAY COIL, SAID THERMOSTAT BEING SUBJECT TO THE TEMPERATURE OF SAID COMBUSTION CHAMBER IN THE REGION OF SAID PRE-HEATER WHEREBY WHEN SAID MAIN SWITCH IS CLOSED, SAID PRE-HEATER WILL BE ENERGIZED AND THEREAFTER SAID PREHEATER WILL CLOSE SAID THERMOSTAT TO ENERGIZE SAID RELAY TO DE-ENERGIZED SAID PRE-HEATER AND SIMULTANEOUSLY ENERTGIZE SAID FUEL VALVE, MOTOR, AND IGNITER TO ESTABLISH COMBUSTION IN SAID HEATER. 